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So I just got my guitar, for the amp I am using the Yamaha THR10II. It doesn't produce any sound when the gain is all the way off. What I'm doing now is turning it up just a little so the amp is able to produce sound. Is this normal?

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    One way to think about this is as the result being gain x volume. Zero x anything is zero, so if either gain or volume is set to zero, you’ll get no sound. – Todd Wilcox Oct 28 '20 at 13:36
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    What guitar are you using? Unless it is active and has a built in amplifier, then it would be strange for it to have a knob labelled 'gain'... – topo Reinstate Monica Oct 28 '20 at 14:01
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    @topoReinstateMonica - most likely the 'gain' pot is on the amp. – Tim Oct 28 '20 at 14:54
  • Most amps have no output with the gain all the way down but some amps do. My Fender Rumble bass head outputs sound to the master at zero gain for example but is the only amp out of 4 I currently own that does this. – John Belzaguy Oct 28 '20 at 18:03
  • You haven't told us what guitar you have. If the pickups are active, there will be batteries in the body of the guitar to drive a pre-amp. If not, the signal is produced electromagnetically by the pickups and will be much weaker. Please tell us the make and model of the guitar and show us a picture of the controls. dawsons.co.uk/blog/… – chasly - supports Monica Oct 28 '20 at 22:05
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Yes it is normal.

The gain is the volume control of the input of the amplifier.

The signal flow of the tube amplifier goes:

Gain (preamp input) to tone stack (eq) to phase inverter stage (input to power amp) to power tubes (amplifier).

Amplifiers that simulate a tube amp follow a similar signal flow.

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Gain is the input level control, it decides how hard the input signal hits the preamp. Guitar amps often exploit the effect of hitting it HARD, overdriving it into distortion.

Volume controls how much the output from the preamp is amplified. Again, specifically on a guitar amp, there may be the possibility of driving the speakers into interesting overload distortion.

On some models the Gain control just goes down to a level expected not to overdrive the preamp. On others it goes down to zero. Either design is 'normal'.

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    This reads clearer than the accepted answer, and points out that gain may go to zero or not depending on design. – Michael Curtis Oct 28 '20 at 21:51
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    And I just got a 'Populist' badge for it! Who'd have known! – Laurence Payne Oct 31 '20 at 15:26
  • Holy, moly! look at the up votes. Well, there is some justice in the this world after all :-) – Michael Curtis Oct 31 '20 at 15:29
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Effectively, there are three controls to your equipment. Volume on the guitar, volume on the pre-amp stage of your amp., and volume on the post, or amplifying stage of your amp.

With any one of those turned all the way down, the signal will not get through its entire path. Guitar volume down - there's no signal from the guitar. Gain down - the guitar signal is not allowed through to be amplified. Output volume on amp., down, any signal won't get amplified.

Those knobs (pots) work as calibrated switches. If any one is off, there's no sound.

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  • "Those knobs (pots) work as calibrated switches" Well, no they don't. They act as pots. Whatever a 'calibrated switch' is? – Laurence Payne Oct 28 '20 at 14:28
  • @LaurencePayne - layman's terms. They go from completely off to completely on gradually. Graduated is a better word. – Tim Oct 28 '20 at 14:51
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    "switches" is a wrong word – blueskiwi Oct 28 '20 at 21:04
  • @blueskiwi - that's why it was in inverted commas. – Tim Oct 28 '20 at 21:14
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Yes, at least some gain is needed. When it's turned off, no signal is being sent from your guitar to the amp.


Gain defines the signal input level to your amp. Thus, if set to 0, there will be no sound produced.

Volume defines the output level of sound.

For example:

Both gain and levels refer to the loudness of the audio. However, gain is the input level of the clips and volume is the output. (SOURCE)

For a guitar-specific example, Fender has an explanation on their website.

A guitar amp can be thought of as a device that has two stages. A relatively weak signal goes from your instrument into the first stage, where it is processed and handed to the second stage, which boosts it into a strong signal-the sound that then comes out of the speakers and rocks the Casbah.

You might also find this post from Sound Design SE helpful: How do you use gain effectively?

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In terms of the electric circuit in the amplifier, gain is defined like:

V(in) x Gain = V(out)

That is, it's not added to the input, it's a multiplier. If you turn the gain down to zero, the output goes to zero as well.

Strictly speaking, "zero" on your amplifier likely doesn't correspond to a gain of zero. The signal coming out of your guitar is too quiet to be heard on its own, and there's a minimum level of amplification needed in order to overcome the electrical losses inside the amplifier and produce something loud enough to hear. "Zero" on an amp generally corresponds to "inaudible", and "Zero plus a smidge" corresponds to "minimum gain required to be barely audible".

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    For a guitar amplifier, I'd describe the behavior as V(out) = Volume x Crunch( V(In) x Gain)). If the V(In) x Gain level is below the point where the crunch affects the signal, the amp will produce a clean tone. The higher that level gets beyond that point, the more distorted the signal will become. Many guitar amplifiers either bias the gain knob so that at its lowest setting, the (V(In) x Gain) level will be just short of the crunch point when the guitar is played loudly, or else have a switch to behave as though the knob is at that position. – supercat Oct 29 '20 at 15:50
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There are at least 2 ways do indicate a gain: in linear units or in logarithmic units (dB).

0 gain in linear units means no signal at the output. You may as well have partial gain (0.1 means 1/10 of the input signal goes to the output).

0 gain in dB means the signal level is not changed. Positive dB values mean increase (amplification), negative - decrease (attenuation) of the signal level. +3dB means 2x increase, +10dB means 10x increase, etc... and -3dB means you get only half of the signal level at the output.

Your gain knob may be labeled either in linear units, in dB, or in some cases, both.

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  • In the dB-type gain case, how is zero actual output accomplished? – Aaron Oct 29 '20 at 19:05
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    @Aaron in theory, it is not accomplished. Zero actual output would be minus infinity in dB. In practice, it is also not fully accomplished as any electronic circuit has some parasitic paths of the signal propagation. Then again, you don't need to go down to zero. You just need the signal to become inaudible. And the distance between the hearing damage and inaudible sound is ~100dB – fraxinus Oct 29 '20 at 19:12
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    Well... even an unplugged electric guitar produces some audible sound in purely acoustic way. So no complete happines in unplugging, either. – fraxinus Oct 29 '20 at 19:36
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    @Aaron In practise, you don't actually get a logarithmic control in dBs. What you get is a control with two (or sometimes more) straight lines which is "kind of" logarithmic over the main range of the control when it's on. It's still fully off at one end. – Graham Oct 30 '20 at 8:58
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    It's good to mention linear and logarithmic units, however guitar / amp knobs usually use neither. Gain should use a “logarithmic tapered” pot (in practice, these aren't really logarithmic, just slower-acting on the lower half of the range), but they're almost always labelled just with an arbitrary 1-10 scale. – leftaroundabout Oct 30 '20 at 9:23
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Man, that's normal, no gain no signal, when your gain knob is set to zero, it's not zero, you just can't hear it, turning the gain up is the only way to drive the signal from the guitar. Everything we use, mics, guitars, headphones require a certain amount of gain. Good luck!!

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